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Transcript of Wind Turbine Drivetrain Testing and Research at the ... · PDF fileMain shaft, gearbox,...

NREL/PR-5000-62887 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Wind Turbine Drivetrain Testing and Research at the

National Renewable Energy Laboratory

Jonathan Keller [email protected]

Pennsylvania State University University Park, Pennsylvania September 15, 2014

2

Wind Power Industry Overview

Wind energy today o Multibillion dollar industry with multinational corporations o 60+ gigawatts (GW) deployed (~5% of U.S. electricity) o Land-based wind @ 7-8 /kilowatt-hour (kWh); beating coal o Leads all renewable technology deployment.

Tremendous opportunity remains o Achieve parity with

natural gas at 56 /kWh

o Establish offshore wind o Provide research and

development (R&D) to achieve 30% wind.

Source: AWEA

http://energy.gov/maps/wind-farms-through-years%23buttn

National Wind Technology Center Overview

4

U.S. Department of Energy National Wind Technology Center

Turbine testing since 1977 Leader in development of design and analysis codes Pioneers in component testing Modern utility-scale turbines

130160 personnel on-site Partnerships with industry, CRADAs, and work-for-others Leadership roles for international standards Offshore wind and marine and hydrokinetic technology development.

Unique test facilities: - Megawatt-scale turbines and sites - Blade testing - Dynamometers - Controls research turbines

Photo by Dennis Schroeder, NREL 30764

5

Current Test Facilities Field

o Field test sites and infrastructure o DOE 1.5, industry megawatt (MW) turbines,

small turbines o Controls Advanced Research Turbines (CARTs) o Research-grade inflow meteorological data.

Drivetrain o 225-kW, 2.5-MW, and 5-MW dynamometers o Dynamic torque testing of fully integrated

drivetrain systems (gearboxes, generators, PE) o Model-in-the-loop (to simulate turbulence). o Non-torque loading to simulate rotor loads

Blade o Static testing and resonant fatigue testing to 50

meters (m) o Accredited (A2LA) fatigue (resonant) and static

testing of blades to IEC standards, modal and blade property measurements, profiling

o Innovative blade test methodology R&D o Massachusetts large blade test facility.

ISO 17025, A2LA-accredited to IEC Standards o Power performance, power quality, acoustic

emissions, structural loads, duration, and structural and fatigue testing.

Photo by Lee Jay Fingersh, NREL 14688

Photo by Dennis Schroeder, NREL 30780 Photo by Lee Jay Fingersh,

NREL 16269

6

Multimegawatt Turbines GE 1.5 MW

o Model: GE 1.5 SLE o Tower height: 80 m; rotor diameter: 77 m o DOE-owned; used for research and education o Turbine commissioned September 2009.

Siemens 2.3 MW o Model: SWT-2.3-101 o Tower height: 80 m; rotor diameter: 101 m.

Alstom 3 MW o Model: ECO 110 o Tower height: 90 m; rotor diameter: 110 m.

Gamesa 2 MW o Model G97 o Tower height: 90 m; rotor diameter: 97 m.

Photo by Dennis Schroeder, NREL 30770

7

New 5-MW Dynamometer 5.8 MW (low-speed shaft) 124 rpm (at full power) 4.6 MNm (3.4 M ft-lb) max

torque Non-torque loads in 5 DOF Dual 75-ton cranes 20 m x 12 m test bay 5 degree drive table tilt

2.5-MW Dynamometer 2.5 MW (low-speed shaft) 1731 rpm (at full power) 1.64 MNm (1.2 M ft-lb) max

torque Non-torque loads in 3

degrees of freedom (DOF) Single 50-ton crane 12.2 m x 15.2 m test bay 06 degree drive table tilt

Dynamometer Facilities

Designed to test entire integrated wind turbine drivetrain system

Photo by Lee Jay Fingersh, NREL 16267

Photo by Robb Wallen, NREL 17400

Photo by Mark McDade, NREL 27249

8

Non-torque loading system

Emulate rotor loading on drivetrain

Produce forces in 5 DOF on test article low-speed shaft while rotating

Up to 7.2 MNm (5.5 M ft-lb) bending moment

Up to 3.5 MN (800,000 lb) axial force

Hydraulic force actuators

High priority for stakeholders.

5-MW Dynamometer Non-Torque Loading System (NTL)

Dynamometer motor 6 MW (8,000 HP)

Dyno non-torque loading system

(NTL)

Dynamometer gearbox 75:1, 3-stage

Test article

Photo by Mark McDade, NREL 28218

Illustration by Scott Lambert, NREL

9

NWTC Controllable Grid Interface (CGI) Facility

o CGI connected to both dynos and some turbines

o Command voltage profiles to emulate real power-line faults

o 7 megavolts-ampere (MVA) continuous with 28 MVA short circuit capacity

Dyno motor 6 MW (8,000 HP)

Dyno non-torque loading

system

Dyno variable frequency

drive Test article power

converter Dyno gearbox 75:1, 3-stage Test article

drivetrain

Test article transformer

Photo by Dennis Schroeder, NREL 25890

Illustration by Scott Lambert, NREL

Gearbox Reliability Collaborative

http://www.nrel.gov/wind/grc/index.html

Sponsor: DOE EERE Wind

11

Wind Turbine Reliability Plant availability often 95%+ o Adjusted for curtailment

Subsystem reliability improving, but still an operation and maintenance (O&M) cost driver o Decrease in downtime of gearbox,

generator, and electrical system o Gearboxes continue to be the largest

source of downtime o Generator, power conversion, and

main bearing not far behind

Need to maintain availability with less cost and effort.

Source: NREL, Wind Stats

Source: GL Garrad Hassan

12

Typical Wind Turbine Drivetrain Architecture

Modular, three-point mounting system o Main bearing and gearbox torque arms

Three-stage gearbox o Ratio of 80 or 100:1 o Three-planet stage(s) o Floating sun o Parallel stage(s).

Generator

Main Bearing Main Shaft

Brake Generator Shaft

Gearbox

Bed Plate

Hub

Torque Arms

13

NREL Gearbox Failure Database

Gearbox failure event data highlighting damaged components, failure modes, and possible root causes o Twenty partners involved in operating ~30% of the U.S. capacity o Number of gearbox failure incidents = 289.

Observations o Bearings 70% o Gears 26% o Parallel section faults

most common o High-speed and

intermediate-speed stage (HSS and IMS) bearing axial cracking most common failure mode.

HSS Bearing Helical Gear

IMS Bearing

Planet Bearing

Planet Gear

14

Photo by Jeroen van Dam, NREL 19257

Gearbox Reliability Collaborative

Test Validate Analyze Redesign Propagate

Potential causes: o Underspecified loads? o Inaccurate design tools? o Inadequate design practice? o Insufficient testing?

Solution process: o Conduct field and dynamometer

testing to measure responses (150+ signals)

o Validate modeling approaches (multibody, finite element analysis)

o Analyze design deficiencies (cylindrical roller bearing [CRB] clearance)

o Redesign gearbox to correct (preloaded tapered roller bearings [TRBs])

o Propagate lessons learned to industry and standards.

Field test

Dynamometer test

Analysis Load cases System loads Internal loads

NREL dynamometer. Photo by Lee Jay Fingersh, NREL 16913

15

GRC Implementation Use smaller 750-kW drivetrain to control costs Lack of public models re-design/re-build commercial gearbox (GB) o First iteration (GB 1&2) brings to state of the art circa 2007 o Second iteration (GB 3) brings to state of the art circa 2012.

Significant internal and external instrumentation o Main shaft, gearbox, coupling, and generator displacements o Planetary section loads, motions, and temperatures o HSS, pinion, and bearing loads recently added.

NREL dynamometer. Photo by Lee Jay Fingersh, NREL 16913

16

New HSS Instrumentation

Slip rings Pinion tooth toot strain for Gear Kh

Bearing strain for relative loading (four axial slots, two Poisson gauges per slot,)

and temperature (both bearings)

Shaft bending strain (two axes, three axial locations,)

and shaft torsion for torque

Encoder for azimuth and speed

Photo by Scott Naucler, NREL 26259

Photo by Jon Keller, NREL 27895

Photo by Scott Naucler, NREL 30252

Photo by Scott Naucler, NREL 30250

Photo by Scott Naucler, NREL 30251

17

Test Summary

Phase 1 (300+ hours of data) o GB 1 field load test

Oil loss event led to GB damage

Phase 2 (700+ hours of data) o GB 2 dynamometer static load test o GB 1 dynamometer test

Condition monitoring and GB teardown

Phase 3 (underway) o GB 2 dyno re-test

HSS loads, dynamic field loads, and generator misalignment

o Improved GB 3 test.

Apr

2009

Oct 2009

July 2010

Nov 2010

Jan

2011

Jan 2013

Jan

2015

Ponnequin Wind Farm. Photo by Jeroen van Dam, NREL 19257

18

Gearbox 1 & 2 Design Deficiencies Non-Torque and Planetary Loads

o Significant effect in three-point configuration

o Cause edge loading on planetary gear teeth